|Year : 2015 | Volume
| Issue : 3 | Page : 664
Rehabilitation of large maxillary defect with two-piece maxillary obturators
Kanchan P Dholam, Karthik M Sadashiva, Pravin P Bhirangi
Department of Dental and Prosthetic Surgery, Tata Memorial Hospital, Mumbai, Maharashtra, India
|Date of Web Publication||9-Oct-2015|
Karthik M Sadashiva
Department of Dental and Prosthetic Surgery, Tata Memorial Hospital, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
The insertion and removal of an obturator in large maxillary defects with or without trismus is difficult. Fabrication of a two-piece obturator in such cases overcomes this problem. This article describes rehabilitation of large maxillary defects with two piece maxillary obturator of three types. All these obturators have a maxillary plate and a bulb component, which are approximated together by various techniques namely, silicone cover, embedded magnets, and press studs. Prosthetic rehabilitation of large maxillary defects with two-piece obturators offers the possibility of adequate oral rehabilitation by fabricating light weight prosthesis, which is easy to use. The bulb covers the undercut areas of the defect enhancing the facial contour and retention. It facilitates easy examination of underlying tissues, recreation of the anatomic barrier between the oral and nasal cavities and restoration of the function and esthetics. Thus, it adds to the quality of life.
Keywords: Maxillary defects, maxillectomy, obturator, rehabilitation, retention, two piece prosthesis
|How to cite this article:|
Dholam KP, Sadashiva KM, Bhirangi PP. Rehabilitation of large maxillary defect with two-piece maxillary obturators. J Can Res Ther 2015;11:664
| > Introduction|| |
Prosthetic obturation is a privileged treatment modality along with microvascular free tissue transfer techniques following maxillectomy. The optimal reconstruction of maxillectomy defects depend on patient characteristics such as age, medical history, tumor stage, and defect size, and on the surgeon's technical expertise. ,, As we assess the advantages of prosthetic rehabilitation over surgical reconstruction, the fact remains that dental rehabilitation is not accomplished in surgical reconstruction in most cases.  Fabrication of an obturator prosthesis offers the possibility of dental rehabilitation and is cost effective. It also facilitates examination of the surgical site for early detection of recurrence. 
A one-piece maxillary obturator is used for acquired defects. Insertion and removal of the obturator is a significant problem in patients with limited mouth opening. Clinical management of this problem can be achieved by surgery, the use of dynamic opening devices and modification of obturators.  A two-piece maxillary obturator is indicated in patients with trismus and in large maxillary defects. It has a bulb component and a maxillary plate which can be with or without artificial teeth. This article describes rehabilitation of a large maxillary defect with two piece maxillary obturators, which are assembled by different mechanisms of adherence. (a) Obturator with a silicon bulb, (b) obturator with embedded magnets, (c) obturator with press studs.
| > Materials and methods|| |
Two-piece obturator with a silicon bulb
This two-piece obturator comprises of maxillary plate with a bulb and silicone cap [Figure 1]a and b. An impression of the maxillary defect is made in irreversible hydrocolloid and a master cast is obtained.
|Figure 1: Two piece obturator with a silicone bulb (a) Maxillary obturator and silicone bulb cap assembled together, (b) Intraoral view of the obturator in the oral cavity, (c) Waxing of the defect: 5 mm thick modelling wax lines the defect with 2 mm border extending the palatal surface of the medial wall, (d) Processing of the silicone bulb, (e) Silicone bulb cap obtained after the processing, (f) Silicone bulb cap lining the intraoral maxillary defect, (g) Pick-up impression of the silicone cap, (h) Master cast obtained with the silicone cap, (i)Maxillary obturator and silicone bulb cap|
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The silicone cap is first fabricated. On the master cast the hollow portion of the defect is waxed. Approximately 5 mm thick extending on to the palate (2 mm) on the medial side of the defect [Figure 1]c. This 2 mm border functions as a vertical stop and facilitates insertion and removal of the silicone cap. Processing of the silicone cap is done (i.e. flasking, dewaxing and packing) with heat temperature vulcanizing silicone (molloplast-B, Regneri GmbH and Co. KG, W-Germany) [Figure 1]d and e. Keeping this silicon cap in the intraoral defect [Figure 1]f, a pick-up impression is made with irreversible hydrocolloid using maxillary stock tray [Figure 1]g. Heat cure acrylic obturator with teeth is then fabricated on this master cast with silicon bulb [Figure 1]h. Fabrication of the obturator with a hollow bulb is done with routine prosthodontic procedures. Full arch wire bending [as shown in [Figure 1]i is the source of retention.
The silicone cover separates the oral cavity from sino-nasal cavities to re-establish function through adequate closure of the defect. It helps primarily in achieving retention by covering the under-cuts on the defect side. It also supports the facial tissues and provides more comfort and stability.
Two piece obturator with embedded magnets
A magnet retained two piece maxillary obturator facilitates easy insertion and approximation of the prosthesis due to the magnetic forces. , This obturator too has a silicon bulb and a maxillary plate. [Figure 2]. After obtaining the master cast of the maxillary defect, the silicone bulb is fabricated in Molloplast-B (Regneri GmbH and Co. KG, W-Germany) with a lining of heat polymerizing acrylic resin of 3 mm thickness, on the palatal surface of the bulb. This acrylic surface houses the north pole of the magnet with the help of autopolymerizing acrylic resin. The south pole of the magnet is embedded on the inner surface of the maxillary plate in approximation with the opposite pole of the magnet in the bulb.
A closed field, permanent, rare earth neodymium-iron-boron, commercially available magnet (Ambika Corporation, New Delhi, India) having 4.5 mm length and 1.3 mm breadth is incorporated into a maxillary prosthesis without interference. It has sufficient attractive force (7.2 N) to prevent displacement of the prosthesis and assist in easy orientation and placement of the maxillary plate.
The magnetic assembly is attached to the heat-cured acrylic plates of the obturator with autopolymerizing resin so that only the terminal surfaces of the magnet plates extend to the outer surface of the acrylic lid. By doing so, the magnets were completely isolated from the oral environment with the bulb and plate of the obturator in place.
Two piece obturator with press studs
A two-piece maxillary obturator is fabricated having a silicon bulb attached with the help of acrylic press-studs on the maxillary plate [Figure 3]. The silicone bulb covering the defect is processed on the master cast with self-curing silicone (Soft Oryl, Teledyne Getz, USA). Three depressions are made on the palatal surface of the bulb. The maxillary plate is fabricated with corresponding elevations to approximate the depressions on the bulb. The two-piece prosthesis with a large flexible and resilient silicone bulb can be inserted comfortably by the patient followed by the acrylic plate being oriented in place using the acrylic press-studs. This makes it an economical option. 
| > Discussion|| |
In large maxillary defects, the obturator bulb extends vertically to engage the surgical defect and horizontally to the lateral aspect of the orbital floor. This increases the size and weight of the prosthesis. This causes soreness and discomfort for the patient as the remaining structures are subjected to continuous stresses. Flexible or resilient material liners such as silicones permit engagement of bony undercuts providing more comfort and stability without compromising retention. 
Silicone material is nontoxic, noncarcinogenic, resilient, hygienic, easy to handle and well tolerated by intraoral tissues. However, it has limitations, such as the increased weight of the prosthesis when used in a bulk form as it cannot be hollowed out. It is expensive with additional costs incurred due to the laboratory procedures for two-stage processing.  The disadvantage of room temperature vulcanizing silicone material such as relative deformation during mastication and susceptibility to monilial infection can be easily eliminated or reduced by using heat temperature vulcanizing silicone, which chemically bonds to the heat cured acrylic plate. 
In case of the two piece obturator with silicone bulb, the large defect results in a heavier prosthesis, to the extent that the force of gravity prevails over the capacity of retention of the substructures and residual elements. In order to reduce the weight of the prosthesis, the bulb portion of the obturator was hollowed after it was processed with acrylic resin. The silicon is used in a thickness of 5 mm around the acrylic bulb as it is adapted well to the tissues in the defect area in comparison to acrylic. The patient benefits from the reduced weight of the obturator, which also offered a harmonic resonance box which enhances the patient's phonation. A hollow maxillary obturator fabricated in acrylic resin may reduce the weight of the prosthesis by up to 33%, depending upon the size of the maxillary defect.  Hence in the other two cases where the bulk of the silicon bulb was more for the ease of use of the patient in cases like poor manual dexterity and trismus, additional modes of retention between the silicon and acrylic portions were required such as magnets and acrylic press-studs respectively. 
Although magnets were not popular in the past, a closed field magnetic system is generally preferred by a prosthodontist.  Complete encasement of the magnetic assembly inside the bulb of the obturator eliminates the cytotoxic effects of corrosion products released from magnets to minimize the effect on local tissues. It also provides greater retention while reducing the magnetic field effect compared to open field magnetic systems.
| > Conclusion|| |
In patients with maxillary defects, surgical procedures cannot provide satisfactory cosmetic and functional rehabilitation. These are compromised people who require physical as well as psychological rehabilitation through a multidisciplinary approach. The two-piece obturator prosthesis provides good comfort to the patients in terms of placement and removal of the obturator in large maxillary defect. The obturator bulb covered the under-cuts on the defect side and separated the oral cavity from sino-nasal cavities to re-establish functionality through adequate closure of the defect to prevent the passage of air, liquid and food. It also supported the facial tissues and provided more comfort and stability without compromising retention. To achieve complete patient satisfaction, informing and instructing patients about obturator use, routine psychological care, and institution of speech therapy should be done. This article describes different techniques of fabrication of two-piece maxillary obturator prostheses.
| > References|| |
Oh WS, Roumanas ED. Optimization of maxillary obturator thickness using a double-processing technique. J Prosthodont 2008;17:60-3.
Devlin H, Barker GR. Prosthetic rehabilitation of the edentulous patient requiring a partial maxillectomy. J Prosthet Dent 1992;67:223-7.
Okay DJ, Genden E, Buchbinder D, Urken M. Prosthodontic guidelines for surgical reconstruction of the maxilla: A classification system of defects. J Prosthet Dent 2001;86:352-63.
Riaz N, Warriach RA. Quality of life in patients with obturator prostheses. J Ayub Med Coll Abbottabad 2010;22:121-5.
Borlase G. Use of obturators in rehabilitation of maxillectomy defects. Ann R Australas Coll Dent Surg 2000;15:75-9.
Cheng AC, Somerville DA, Wee AG. Altered prosthodontic treatment approach for bilateral complete maxillectomy: A clinical report. J Prosthet Dent 2004;92:120-4.
Javid N. The use of magnets in a maxillofacial prosthesis. J Prosthet Dent 1971;25:334-41.
Federick DR. A magnetically retained interim maxillary obturator. J Prosthet Dent 1976;36:671-5.
Mishra N, Chand P, Singh RD. Two-piece denture-obturator prosthesis for a patient with severe trismus: A new approach. J Indian Prosthodont Soc 2010;10:246-8.
Srinivasan M, Padmanabhan TV. Rehabilitation of an acquired maxillary defect. J Indian Prosthodont Soc 2005;5:155-7.
Wu YL, Schaaf NG. Comparison of weight reduction in different designs of solid and hollow obturator prostheses. J Prosthet Dent 1989;62:214-7.
Kumar NS. Prosthetic rehabilitation of a complete bilateral maxillectomy patient: A technical report. Aust J Basic Appl Sci 2009;3:424-31.
Bae HE, Jeon JH, Chung MK. Rehabilitation of a patient with a postradiotherapy trismus with an obturator and a maxillary denture using magnet attachments. J Korean Acad Prosthodont 2008;46:586-9.
[Figure 1], [Figure 2], [Figure 3]